[MIG] account_financial_report: Migration to 14.0

Since v14, Odoo defines the `__slots__` attribute in the `BaseModel` class (ea3e39506a)
This makes it impossible to add attributes to an instance like it was done here in v13.
The use of the `report_data` dictionary passed between method is the closes and simples solution to this "issue".

TT26415

Co-authored-by: Alex Cuellar <acuellar@grupoyacck.com>

account_financial_report/models/__init__.py

@@ -1,4 +1,4 @@
-from . import account
 from . import account_group
+from . import account
 from . import account_move_line
 from . import ir_actions_report